replacing front cab corners (everything comes together in that one place)

[sircrunch]

if I'm replacing outer rockers, inner rockers, floor pans, kick panels, brace, and the lower front pillar, how can I do this without letting the cab sort of fall in on itself slightly? can I replace one piece at a time just to keep the structural rigidity? If so, what order would be easiest to replace in? A friend of mine said he cut all of it out at one time and just let it hang, then he said he just aligned everything up by mounting the doors and fenders until he had the right gaps, then spotwelded. that seems wrong to me. any pictures, any advice? maybe bracing is the answer, if so.. any advice or pics on that? I'm HOPING someone tells me it can be fixed one piece at a time to keep the structure of the truck from caving in slightly.... I don't wanna mess up big time here